Inhaled corticosteroids and mortality in COPD

In his letter published in the August edition of Thorax, Dr Stirling¹ raises many issues regarding the role of inhaled corticosteroids in chronic obstructive pulmonary disease (COPD). As pointed out by Dr Stirling, there are compelling data to indicate that inhaled corticosteroids reduce clinically relevant exacerbations by nearly a third and improve health status and quality of life for patients with COPD.²,³ They also reduce emergency visits and hospital admissions.⁴ Our pooled analysis extends these findings by demonstrating a salutary effect on mortality.⁵ The precise mechanism(s) by which these effects occur are uncertain.

COPD is an inflammatory disorder which is characterised by both local lung and systemic inflammation⁶,⁷ and the intensity of the inflammatory process relates to COPD progression.⁸ Inhaled corticosteroids appear to attenuate lung and systemic inflammation.⁹,¹⁰,¹¹ However, inhaled corticosteroids have pleotropic effects and some of these effects—such as restoring β₂ adrenoceptor sensitivity and reducing oxidant load in the airways—may be of relevance in COPD.¹² As such, it would be premature and presumptuous to attribute the clinical benefits exclusively to their anti‐inflammatory properties. While oral corticosteroids are more powerful anti‐inflammatory agents than are inhaled corticosteroids, they are also fraught with many side effects.¹³ Accordingly, they cannot be recommended for long term use in most patients.

We agree with Dr Stirling that there are other effective interventions in COPD—including smoking cessation, pulmonary rehabilitation, and co‐morbidity management—that deserve attention.¹⁴ Inhaled corticosteroids should not replace any of these effective interventions; rather, they should be regarded as complementary therapies in the management of COPD.